The invention relates to a camshaft drive of a multi-cylinder V-engine of the type where the valves are actuated by two camshafts respectively which are assigned to a cylinder bank, said camshafts being disposed overhead and being driven by the crankshaft by way of an intermediate timing gear.
From the U.S. Pat. No. 3,110,195, a camshaft drive for a V-engine is known in which an intermediate timing gear engaging in a crankshaft gear wheel drives one camshaft by way of another gear drive which, in turn drives the second camshaft also by means of gears. Because of the high noise emission, this type of a camshaft drive, at most, can be used for racing engines but is unsuitable for production cars.
It is an object of the invention to provide a compact camshaft drive which requires little space, causes less noise and contributes to the damping of torsional vibrations originating from the crankshaft and the camshafts.
According to preferred embodiments of the invention, this object is achieved by providing an arrangement wherein the camshaft drive is arranged close to an engine flywheel at an output end of the crankshaft, and wherein the intermediate timing gear has a gear wheel mating with a crankshaft gear wheel as well as two sprocket wheels by means of which, in each case, the two camshafts of one cylinder bank are driven by means of a chain. Since a chain drive is used for driving the camshafts from the direction of the intermediate timing gear, the transmission line becomes noticeably quieter and contributes to the damping of vibrations. The reason is that the chains have a certain elasticity in contrast to the rigid gears and are therefore able to dampen the amplitudes of the vibrations introduced into them. If the camshaft drive is arranged close to the flywheel on the output end of the crankshaft, it is situated at a point of the crankshaft which has particularly low vibrations so that a long service life and a lower noise level are ensured even at the highest engine speeds.
Reference is also made to related commonly assigned U.S. patent application Ser. No. 07/546,882, filed Jul. 2, 1990, (based on German application P 39 21 715.9, filed Jul. 1, 1989.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.